Electric switch



April 2, 1932. G. H. DoRGl-:LOH ET AL.

ELECTRIC SWITCH Filed March 1'5, 1930 details of the mountiig PatentedApr. l2, 1932 UNITED -STATES PATENT OFFICE GEORGE E. DORGELOH, OIPEASTORANGE, THOMAS I. MASLIN, F BLOOMIIELD, NEW JERSEY, ASSIGNORS TO GENERALELECTRIC COMPANY, A CORPORATION 0F NEW YORK ELECTRIC SWITCH Applicationled Iarch 15, 1980. Serial No. 433,195.

Our invention relates to electric switches and more particularly to ushbutton master switches and has for its o ject the provision of animproved form of switch of small overall size but of ample currentcarrying and interrupting capaclty in which speclal provision is madefor insuring a rolling and wipin action between the switch contacts inor er to obtain self-cleaning operation. Our improved form of switchalso provides for ease of mounting and wiring and involves onl arelatively few parts of simple, rugged an inexpensive construction.

While not necessarily limited thereto, the

improvements of the present invention are particularly adapted for usein a double acting push button, master switch for controlling bothnormally open and normally closed circuits. In carrying the inventioninto effeet in such a switch, a single bridging contact member isemployed for roviding a double break in both the normal y open andnormally closed circuits and is so mounted on a special off-centerrocking pin associated with the push button operating rod that therolling and wipin action of the bridging member is obtaine uponengagement thereof with each of two pairs of stationary contacts mountedin opposing spaced alignment.

In the accompanying drawings Fig.. l is a perspective view of a doubleactin push utton master switch embodying t e improvements of the presentinvention; Fig. 2 1s a sectional view revealing more clearly thearrangement for the bridging contact and igs. 3, 4, 5 and 6 showdiagrammatically the relative positions of the bridging contact as itwipes into engagement with the upper and lower pairs of stationarycontacts.

In the preferred form shown in Fig. 1 the double acting push buttonswitch comprises a base or frame 10, preferably formed of mouldedinsulating material with an open slot 11 located in one side thereof.The pair of stationary contacts 12 are mounted on the block in spaced aart relation at one side of the slot 11, pre erably being held inposition by rivets anchored in the holes 13 formed in the base 1.0. Theblock 10 is suitably formed to provide easy access to the terminalscrews 14 by means of which the circuit conductors are connected to thestationary contacts 12.

A second pair of a stationary contacts 15 are mounted on the block 10 onthe opposite side of the slot 11, also preferably by means of rivets 16.The upper portion 17 of tho block 10 preferably is cutaway t0 permitready access to the terminal screws 18 provided for connecting thecircuit terminals to the stationary switch Contact 15.

The bridging contact member 20 is mounted for movement between the pairsof stationary contacts 12 and 15 on the opposite sides of slot 11. Asmore clearly shown in Fig. 2, the bridging contact is 'mounted on thereci rocating operating rod 21 which carries t e push button 22 at thisupper end. The operating rod 21 preferably is of square or rectangularcross section and has a freely sliding non-rotatable fit with a suitableopening formed inthe u per portion 17 of the block 10. The reducedOsection 23 at the lower end of the operating rod 21 is screw-threadedand carries the projecting collar or washer 24, which is held inposition by the nut 25 and lock washer 26. It will be observed that thebridging contact 20 is provided with an cifcenter rocking pin 27, whichpreferably 1s formed by punching out the metal of the contact member asindicated in the drawing. The non-circular opening 28 in the bridgingcontact member is made somewhat larger than the cross section of theoperating rod 21 extending therethrough so as to permit free tilting androcking movement of the bridging contact member on the rocking pin 27when the bridging member engages with thehstationary contactscooperating therewit It will be noted that the bridging contact member20 is provided with the skewed contact portions 30 and 3l which-projectslightly upward and downward from the opposite edges of the bridgingcontact so as to engage respectively with the upper stationary contacts12 and the lower stationary contacts 15. In order to yieldingly bias thebridging contact 20 to a position in laterally skewed loo Yoperating'rod 21 andthe bridging contact 20.

With the bridging contact 20 thus biased to a position in laterallyskewed alinement with Y 'the stationary contacts, the contact portions30 at one ed e of the bridging contact'20 are equidistant the contactportions 31 at the opposite edge of the brid 'ng contact 20 also areequidistant from t e stationary contacts but are at a different distancethan the contactportions 30. In other words,pboth contact portions 30and 31 are in alinement with the stationary contacts but the twoportions 30 and 31 are laterally skewed with respect to the stationarycontacts. Likewise in order to bias the bridging contact intoengagementwith the upper pair of stationary contacts 12 and out ofengagement with the lower pair of contacts 15, the biasing spring 34 isinterposed between the. ush button 22 and the top of the block 10. Tiiebiasing spring 34 is somewhat stronger than the blasing spring 32 andhence serves to operate the bridging contact 2O to the tilted positionin which it is shown in Fig. 2, thereby compressing the spring 32.

With the switch thus constructed, the bridging contact 20 normallycloses the circuit throu h the stationary contacts 12 and consequentynormally opens the circuit through the stationary contacts 15. Uponoperation of the push button 22 to disengage the bridging contact 20from the stationary contacts 12 and operate the same into engagementwith the stationary contacts 15, the tilting and rocking motion impartedto the bridgingcontact 20 is as follows: As the operating vrod 21 islowered, the biasing spring 32 serves to rock the bridging contact 20 onthe rocking pin 27 until the portion of the bridging contact 20, on theopposite side of the operating arm 21 from the rocking pin 27, restsupon the shoulder 24. In this way, as shown in Fig. 3, the skewedportions 30 of the bridging contact 20 are substantially simultaneouslydisengaged from the pair of spaced apart stationary contacts 12.Thereafter the bridging contact 2() is maintained on the operating rod21 in skewed alignment with each pair of the stationary contacts. As thedownward movement of the operating rod 21 is continued, the skewedportions 31 extending downward from the rear edge of thebridging contact2O are brought substantially simultaneously into engagement with thelower pair of stationary contacts 15. The substantially simultaneousdisengagement of the bridging contact 20 from thestationary contact 12enables a simultaneous double break to be obtained which is mosteffective in interrupting the current in the circuit. Also thesimultaneous double break distributes the arcing duty between the conromthe stationary contacts and tacts and thereby prevents localized burningor pitting of any particular contact. Moreover, due tothe rocking actionof the bridging contact 20, any burning or pitting of the `jectingportions 31 to wipe and roll on the stationary contacts 15 therebycleaning away any dirt, dust or other impediment that might prevent Goodelectrical conductin contact between tie bridging contact 20 and thestationary contacts. This wiping action thus maintains the contacts in aclean condition.

Upon the release of the push button 22, the biasing spring 34 returnsthe bridging contact 20 to its initial position. Durin this operation,the brid ing contact 20 sugstantially simultaneousIy disengages thelower pair of stationary contacts 15 returns to its position in skewedalignment with the stationary contacts so that the skewed projectingportions 30 substantially simultaneously engage the upper paix.` ofstationary contacts 12. The further upward movement of the operating rod21 serves` to tilt the bridging contact 20 about the rocking pin 27 andin this way produce a wiping, rolling action of the skewed portions 30on the statlonary contacts 12 as illustrated in Figs. 3 and 4.

Provision is made for readily mounting the switch by roviding the recesshole 36 in the block 10 or receiving a holding down screw or bolt. Inorder to prevent turning of the block 10 about'the holding down screw orbolt, the projecting boss 37 is formed to be received into a suitableopening in the member upon which the switch is mounted.

From the foregoing it will be seen that the improved double actingswitch embodying the present invention is not only of compact, rugged,and inexpensive construction, permitting ease of mounting and wiring,but also effectively insures self-cleaning, wiping action between thecontacts so as always to obtain good contact engagement therebetween.

What we claim as new and desire to secure by Letters Patent of theUnited States, is,

1. A switch comprising a pair of spaced apart stationary contacts, abridging contact therefor, amovable operating member for the bridgingcontact, and means for tiltably mounting the bridging contact on theoperating member in skewed alignment with the stationary contacts toeffect substantially sil'IE multaneous engagement and disengagementtherewith with a wiping action.

2. A switch comprising a pair of spaced apart stationary contacts, abridging contact therefora movable operating member for the bridgingcontact, and means including a rocking pin for tiltably mounting thebridging contact on the operating member in skewed alignment with thestationary contacts to effect a wiping action upon engagementtherebetween.

3. A switch comprising a pair of spaced apart contact plates, a bridgingcontact therefor having skewed projecting portions at the edge thereoffor engaging with said stationary contact plates, a movable operatingmember having the bridging contact tiltably mounted thereon, and meansfor biasing the bridging contact to a position in laterally skewedalinement with the spaced apart contact plates for effectingsubstantially simultaneous disengagement and engagement of the skewedprojecting portions .of the bridging contact with the stationary contactplates with a wiping action.

4. A switch comprising a pair of spaced apart stationary contact plates,a bridging contact having skewed projecting portions at one edge thereoffor engaging with said stationary plates, a movable operating member forthe bridging contact, and means including a rocking pin for tiltablymounting the bridging contact on the operating member in laterallyskewed alignment with the stationary contact plates to effect a wipingaction upon engagement therebetween.

5. A double acting switch comprising two pairs of stationary spacedapart contacts mounted in opposing alignment, a movable bridging contacthaving oppositely skewed projecting portions at the opposite edgesthereof for engaging with the stationary contacts, and an operatingmember extending between the opposing airs of stationary contacts andhaving the ridging member tiltably mounted thereon.

6. A double acting switch comprising two pairs of stationary spacedapart contacts mounted in opposin contact havin oppositely skewedprojecting portions at te opposite edges thereof for engaging with thestationary contacts a movable operating member for the bridging contact,and means including a rocking pin for tiltably mountin the bridgingcontact on the operating mem er in laterally skewed alignment with eachpair of the stationary contacts to eect a wiping action upon enga ementtherebetween.

n witness whereof, we have hereunto set our hands this 13th dav ofMarch, 1930. GEORGE H. DORGELOH. THOMAS I. MASLIN.

relation, a bridging

